1. Field of the Invention
The present invention relates to a heat developable light-sensitive material, and more particularly relates to a heat developable light-sensitive material employing a diazonium salt.
2. Description of the Prior Art
Various heat developable light-sensitive materials have hitherto been known. A typical example thereof is a heat developable light-sensitive material employing a diazonium salt, which is composed of a support having coated thereon a light-sensitive layer containing as essential components a light-sensitive diazonium salt, a coupler and a compound capable of generating an alkaline substance under heating, which compound is, hereinafter, referred to as an alkali-generating agent. When the light-sensitive layer of the material is exposed and then heated, desired photographic images can be formed.
In heat developable light-sensitive materials, there have been various problems that have not been easily solved. For example, since a diazonium salt, a coupler and an alkali-generating agent in the light-sensitive layer must be selected so that the reaction temperature of the diazonium salt and the coupler, and the thermal decomposition temperature of the alkali-generating agent are within a suitable range, it is troublesome to select the combination of the components; since the alkali-generating agent present in the light-sensitive layer is often gradually decomposed at room temperature (e.g., about 20.degree. .about. 30.degree. C.), it is very difficult to protect the properties of the light-sensitive materials from deterioration even if they are stored at room temperature; and since an alkaline substance such as ammonia gas is generated by developing the heat developable light-sensitive materials, ventilation of the room where the development is carried out is necessary and environmental pollution problems inside and out of the room occur.